• Journal of Biosystems Engineering
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• v.24 no.2
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• pp.167-178
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• 1999

In the path of agricultural development, agricultural mechanization has played some decisive roles such as protecting natural disaster, substitution of labor shortage in agricultural production and so on. In making our country's agricultural mechanization plan, Japanese agricultural mechanization policy has been frequently referred to but it's very hard to find informative data for systematic analysis of the mechanization policy. In this paper it was tried to analyze the resent trend in Japanese agricultural mechanization policy and it's performance with many materials published in Japan. As the results, four things are recommended to be considered in making Korean agricultural mechanization policy. First, faster enlargement of agricultural machinery size in Korea might be very harmful to drop down agricultural production cost. Second, diverse utilization methods of agricultural machniery should be introduced. Third, a marketing of the used agricultural machinery must be activated to reduce agricultural production cost. Lastly, the joint R & D for developing low price agricultural machniery is necessary for small markets.

• The Journal of Korea Robotics Society
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• v.6 no.4
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• pp.308-316
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• 2011

This work deals with development of effective redundancy resolution algorithms for the motion control of manipulator. Differently from the typical kinematically redundant robots that are attached to the fixed ground, the ZMP condition should be taken into account in the manipulator motion in order to guarantee the system stability. In this paper, a new motion planning algorithm for redundant manipulator not fixed to the ground is introduced. A sequential redundancy resolution algorithm is proposed, which ensures the ZMP (Zero Moment Point) stability, the planned operational motion, and additional sub-criteria such as joint limit index. A geometric constraint equation derived by reshaping the existing ZMP equation enables one to employ the sequential redundancy algorithm. The feasibility of the proposed algorithm is verified by simulating a redundant manipulator model.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.133-136
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• 1996

The nozzle dam task is essentially needed to maintain and repair nuclear power plants. For this task, an 8-dof redundant robot is studied with a local path-planning method[l] which is effective to find the optimal joint path in the constrained environment. In this paper, the method[l] is improved practically with the weight matrix and efficient algorithm to find working set. The effectiveness of the proposed method is demonstrated by simulation and animation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.5
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• pp.430-434
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• 2011

Extraskeletal osteochondroma is an uncommon benign tumor that arises in soft tissues lacking continuity with an adjacent bone and joint. Due to similar histopathological findings, extraskeletal osteochondroma is often misdiagnosed for a conventional osteochondroma, the most common benign tumor that arises from the epiphyseal plates of long bones. The pathogenesis of extraskeletal osteochondroma is unclear, but metaplasia of synovial mesenchymal tissue is the best supported etiology. The most common sites of extraskeletal osteochondroma are the hands and feet, and it is rarely found in the maxillofacial area. We present a case of a two-year-old boy with a giant extraskeletal osteochondroma that developed in the masticatory space of the mandible along with a review of the relevant literature.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.14-26
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• 2020

We categorize partnership types between network operators and a global video streaming or over-the-top service provider, Netflix from 2011 to the first quarter 2018. The options are based on the integration of over-the-top (OTT), Netflix with pay TV and telecommunication operators in the form of carrier billing, access to over-the-top (OTT) via devices or the development of their tariff plans. Options of the Type 3, 'cooperation' or the Type 4, 'agreement' entails a kind of the technical involvement between two partners and commercial agreement. The types of partnership are evolving from one to others. Some partnerships have characteristics of more than one type. The majority of technical or service integration cooperation of Type 3 entail bundling and marketing promotion of Type 2 and Type 1. Similarly, the 'agreement' of Type 4, co-branded or white-label service initiative entail tariff or device user interface (UI) integration of the 'cooperation' of Type 3 and joint marketing initiatives of Type 1.

• The Journal of Korea Robotics Society
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• v.12 no.3
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• pp.258-262
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• 2017

In this paper, we propose a new collision detection algorithm for human-robot collaboration. We use an IMU sensor located at the tip of the manipulator and the kinematic behavior of the manipulator to detect the unexpected collision between the robotic manipulator and environment. Unlike other method, the developed algorithm uses only the kinematic relationship between the manipulator joint and the end effector. Therefore, the collision estimation signal is not affected by the error of the dynamics model. The proposed collision detection algorithm detects the collision by comparing the estimated acceleration of the end effector derived from the position, velocity and acceleration trajectories of the robot joints with the actual acceleration measured by the sensor. In simulation, we compare the performance of our method with the conventional Residual Observer (ROB). Our method is less sensitive to the load variation because of the independency on the dynamic modeling of the manipulator.

• Journal of the Korean Data and Information Science Society
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• v.26 no.4
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• pp.971-984
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• 2015

Imputation procedures fill-in missing values, thereby enabling complete data analyses. Fully efficient fractional imputation (FEFI) and multiple imputation (MI) create multiple versions of the missing observations, thereby reflecting uncertainty about their true values. Methods have been described for hypothesis testing with multiple imputation. Fractional imputation assigns weights to the observed data to compensate for missing values. The focus of this article is the development of tests of independence using FEFI for partially classified two-way contingency tables. Wald and deviance tests of independence under FEFI are proposed. Simulations are used to compare type I error rates and Power. The partially observed marginal information is useful for estimating the joint distribution of cell probabilities, but it is not useful for testing association. FEFI compares favorably to other methods in simulations.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.11a
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• pp.20-21
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• 2019

The Joint Video Experts Team (JVET) has been working on the development of next generation of video coding standard called Versatile Video Coding (VVC). Position Dependent Intra Prediction Combination (PDPC) which is one of the major tools for intra prediction refines the prediction through a linear combination between the reconstructed samples and the predicted samples according to the sample position. In VVC WD6, nScale which is shift value that adjusts the weight is determined by the width and height of the current block. It may cause that PDPC is applied to regions that do not fit the characteristics of the current intra prediction mode. In this paper, we define nScale for each width and height so that the weight can be applied independently to the left and top reference samples, respectively. Experimental results show that, compared to VTM 6.0, the proposed method gives -0.01%, -0.04% and 0.01% Bjotegaard-Delta (BD)-rate performance, for Y, Cb, and Cr components, respectively, in All-Intra (AI) configuration.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.1
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• pp.163-170
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• 2001

In this paper, a massless link model transmitting external forces is developed to achieve the numerical efficiency in simulation of vehicle suspension systems. Forces acting on links are resolved and transmitted to attached points with a quasi-static assumption. Also, a theoretical derivation and computer implementation of a massless link with bushing elements are proposed. In the massless link with bushing elements, one end is connected to the adjacent body with bushings and the other end is connected with a spherical joint. The deformation of a massless link with bushing elements is theoretically determined by minimizing the potential energy function with quasi-static equilibrium assumption at each time step. Several simulations with a full vehicle model are carried out to compare the efficiency of the developed massless link component. From the results, it is concluded that the proposed approach can reduce the computational time considerably.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.45-48
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• 1997

The low frequency pulsed MIG welding process of new current waveform control to switch over unit pulse conditions (pulse current, pulse duration) in the fixed cycle was developed and its effect were investigated for aluminium and its alloy. By using this new welding process, the bead appearance having clear ripple pattern, such as TIG welding bead can be obtained and the gap tolerance of lap and butt welding joint can be expanded.